Condensed Matter Theory Seminar - Cenke Xu - “Topology and Quantum Criticality under Weak-Measurement or Decoherence”

We investigate the fate of generic quantum many-body states under weak-measurement or decoherence. In particular, we focus on two large classes of systems with novel features under weak measurement: the quantum criticality, and topological states. We employ a powerful quantum field theory and path integral technique to analyze both classes of systems. As examples, we will demonstrate that weak-measurement can drive a Wilson-Fisher fixed point into the exotic “extraordinary-log” phase that was discovered recently in a different context. Furthermore, we demonstrate that a Chern insulator state can generate multiple conformal field theory partition functions under decoherence.